Actor Will Smith offered apologies Monday to Chris Rock for smacking the comedian during the Oscars ceremony, as the body that oversees the awards said it was launching a formal review of the incident.
Smith -- who was named best actor on the night -- marched onto stage during the glitzy Hollywood ceremony and hit Rock over a joke about wife Jada Pinkett Smith's hair.
"I would like to publicly apologize to you, Chris. I was out of line and I was wrong. I am embarrassed and my actions were not indicative of the man I want to be," the "King Richard" star wrote on Instagram.
"Violence in all of its forms is poisonous and destructive. My behaviour at last night's Academy Awards was unacceptable and inexcusable," Smith said.
"Jokes at my expense are a part of the job, but a joke about Jada's medical condition was too much for me to bear and I reacted emotionally."
Pinkett Smith suffers from alopecia, a condition that causes hair loss, and had a closely cropped head at Sunday's ceremony.
The 94th Academy Awards was in its final hour when actor and comedian Rock quipped that Pinkett Smith appeared ready to star in "G.I. Jane 2" -- a putative sequel to a film about a female soldier who has a shaved head.
After at first appearing to laugh at the joke, Smith walked onto the stage and smacked Rock with an open hand.
He then returned to his seat and shouted: "Keep my wife's name out of your fucking mouth."
Smith tearfully apologized to his fellow nominees and the Academy -- but not Rock -- a few minutes later as he accepted his historic Oscar.
"Love will make you do crazy things," he said.
On Monday, he repeated that apology.
"I would also like to apologize to the Academy, the producers of the show, all the attendees and everyone watching around the world.
"I would like to apologize to the Williams Family and my King Richard Family. I deeply regret that my behavior has stained what has been an otherwise gorgeous journey for all of us.
"I am a work in progress."
Smith's mea culpa came hours after the Academy condemned his behavior and said it was looking at possible sanctions.
"We have officially started a formal review around the incident and will explore further action and consequences in accordance with our Bylaws, Standards of Conduct and California law," a statement said.
Celebrities from Tinseltown and beyond reacted with shock and stunned amazement to Smith's outburst, with some defending him and others condemning a display of "toxic masculinity."
"He could have killed him. That's pure out of control rage and violence," filmmaker Judd Apatow said in a tweet he later deleted.
"Stand-up comics are very adept at handling hecklers. Violent physical assault... not so much," "Star Wars" icon Mark Hamill chipped in.
The comedy world was quick to rally to Rock's side, complaining that Smith's outburst could spark copycat behavior, endangering other stand-ups.
Emmy Award-winning Rosie O'Donnell called out a "sad display of toxic masculinity from a narcissistic madman," while Kathy Griffin added: "Now we all have to worry about who wants to be the next Will Smith in comedy clubs and theaters."
Booker prize-winning author Bernadine Evaristo suggested that Smith had not just wrecked what should have been his greatest triumph, but had also sullied his legacy.
"Only the fifth black man in nearly 100 years to win an Oscar for male lead, and the first in 16 years, resorts to violence instead of utilizing the power of words to slay Chris Rock. Then he claims God and Love made him do it," she said.
Smith went from the Oscars to the Vanity Fair after party, where he and his family posed for photos.
Inside, he was filmed dancing and singing along to his 1991 smash "Summertime."
Some celebrities came to Smith's defense, with singer Nicki Minaj saying that as her husband, Smith was privy to the pain Pinkett Smith endures.
"You just got to witness in real time what happens in a man's soul when he looks over to the woman he loves & sees her holding back tears from a 'little joke' at her expense," she tweeted.
"This is what any & every real man feels in that instant. While y'all seeing the joke he's seeing her pain."
Some social media users called for Smith to be stripped of his Oscar, but Academy governor and Oscar winner Whoopi Goldberg said that would not happen.
"We're not going to take that Oscar from him," she said on daytime TV show "The View."
"There will be consequences I'm sure, but I don't think that's what they're going to do."
One Academy voter, who wished to remain anonymous, said it was frustrating how the incident had dominated coverage.
"I would have preferred the story being about the great diversity of the Awards show, which now seems secondary," the person told AFP.
"A female director won, an actor from the disabled community won, as did an actress of the LGBTQ community."